Retreading tire curing rim



Dec. 23, 1958 c. D. HElNzE 2,865,053

RETREADING TIRE CURING RIM Filed Jan. ze, 195e Fig.|

CHALMER D. HEINZE INVENTOR.

United States Patent W 2,865,053 RETREADING una CURING vRIM--ChalmerDJHeinzQ Galisle,`-Pa., assgnor to Carlisle Corporation, arcorporationfof Delaware Application January 26, 195,6, fseriaiN.561,474 solaims. l(ci. irs-:45)

The present Vimproven'rents arelate 5to :vulcanizirig appa- :fatus vforuse finzretreading worn or tlamaged 4pneumatic tires, and moreparticularly :tozthe collapsible curing rim Vstructure employedtherewith,

. That portion ofthe conventionalvulcanizing apparatus Whichrelatestothey present invention consists-of a matrix, or moldrint'owhichthegtiredsgplaced which istolreceive the retread. An-ar bagis=customarilyzinserted in `the `tire,.andfthen a collapsible curing rimis alsoinserted in the tire, and the air bag is inated, therebypressingitself and the inner rim againstthe .inner .walls ofthe tire to holditin :rigid position inthematrix or mold. The rim is circular andrigid,sothatthe inated air bag `servesto presszthe tire against the mold.

Because-oftheuse `of tiresofmany different sizes, the `small shop:orgarage which solicits `retreading business must stock curing -rimsof.many.diiferent sizes. vObviouslya curing rim ,of asmall size,`wheninserted in a tire of .twice the-size, .Will preventtheair fbagfromperforming its proper function, and will in time, cause the air bag tolose its efficiency and to depreciate rapidly. .It is thereforeobviousthat ashop in the retreading business, :must keep asupplyofcuring rims of many different sizes .ifit is-to handle the traderesulting from many different sizes of tires.

AA primary object o-f the invention, therefore, Ais to provide Va-single tirecuring rim structure unit which will serve in retreading aplurality of sizes of tires.l A further object is to provide -animproved collapsible curing rim structure which is automaticallyadjustable to various tire `sizes in response to inllation of theconventional air bag.

Another |object of the improvements is to provide a unit of theaforementioned type, which has complementary annular structures havingcommon diameters, 4so that the parts will be in register, withanoverlapping flangestructure Xed to one section and telescoping`aportiony of the other. A further object is to pro-vide a device of theaforementioned character, which is yieldingly maintained in operativeposition by resilient means `such as spring members `and the like, sothat the parts will always be preserved in cooperative relationship.

A furtherobject is to provide a curing rim structure having an offsetllange element for defining a recess for receiving the ,complementaryrim structure, and of sucient width ,to present a continuous surfacewhen the rim isfully expanded.

A Afurther object of the improvements is to provide `an endless,collapsible curing rim structure unit, having self- ,adjusting featuresand having annular beadportions with convex surfaces for engaging theinner walls `of the tire. These and other objects of the improvementswill appear as the description proceeds. The preferred embodiment isillustrated in .the accompanying drawings vin which:

Fig. vl is an enlarged section of the collapsible curing rim structureunittaken on line 1-1 of Fig. 3.

Fig. 2 is a fragmentary plan View of the segments at ,Patented Dec. 23,195s ice jtheir end-to-endjuncture, looking in the direction of the-arrows indicated at line 2-2 of Fig. 3, parts being broken away to showthe overlapping flange.

Fig. 3 is a side elevationof the entire `curing rim structu're unit,A-shown in miniature, for convenience in `illustration, and shown -infull circumferential or annular form.

'Referring tothe drawings, Fig. 3 illustrates, on -a reduced scale,.aside elevation ofthe curing rim unit of the present improvements invfull circumferential or an- :nularpositionasiit exists when positionedwithin the tire to be retreaded. VThis unit comprises .a plurality ofsegments 1, 2, 3, `4 and 5, movably attached in end-to-end relationshipso asto `define an endless ring. vInthe .illustrated embodimentthese:segmentsare of yvarying linear extent.

1-In thezpreferre'd embodiment,.these `segments are hinged together bypivotpins `6 and 6a,.extending.through` ears17, integrally.connectedwiththe ends -ofadjacent segments.

lA suitablefbossf' surrounds eachpivot pint anda for Pins 6 are handles9 and 10 are provided for receiving-a suitable tool. (n ot Show-rr)or-.manipulating the unit to and from fullgcircularposition .or ,to :andyfrom collapsed position.

' As aforesaid, the segments-1 to5 are of differentlinear extent, tofacilitatercollapsing andinsertion of theunit within the tire carcass.

Conventional `curlrrg ,rims khave the vgeneral transverse contour-of therimillustratedin Fig. 'Lextending from `bead ;B ,in anarclto beadC.These conventional-rims ,consist of appluralityof segments attached inamanner to dene a ring. In the present improvements, however,

.these segments arejsplit longitudinally orcircumferentialvllygof thering.unit, todene a subsegment l11 and subseg- -ment 12, ,which,gas seenin Fig. l, are in register, are

complementando-one another, and Valso denecomple- -mentaryannularcollapsible `rim structures.

While the provisionof pins;6,.6a, ears ,7 and bossesS,

, serve to retain thesegments yin end-to-endrelations'hip,

.is welded,orotherwise fixed to sub-segment 12 and `pro- -vides -a lfreehousing within which bolt 14 may reciprocate. A coilspring .17 surroundsa portion of bolt 14 `-and hasitsends-engaging washer 20in front of nut1S andsleevewl.

lIt .isapparent from the foregoing description'that when partslll .and12 are spread `or expandedthe,springs 17 will beplaced,undeifcompression so that uponrelease of pressurethe springs willrestore the1 parts to the position shown in Fig. 1. This yieldable boltand springde- `vice, permitsspreadingof the p arts V11 and 12 to anyv,desired degree to y2l.QQOnIIlIIlodate diiferent tire sizes.

, Meansforlimiting the spread of thesegments 11 and l12, may be providedin various forms. The preferred formillustrated in Fig. l consists inproviding recesses in `erachholu'sing such asrecesslja. `One end ofthespring ,17 isnes'tedtherein, while the outer end engages washer 20 onbolt ,14 and retained by nut 15. `The,diameter of ythe `washer 2,0 is,substantially the width of the housing 16. Accordingly, during themovement of the segments V11` and 12 to a spread position, the spring17'is compressed until washer 20 meets end 21 of housing 16.

This engagement arrests further spreading of the segments.

Itis apparent that the nut 15 may be set at any one of various positions-along the bolt 14. In this manner, the degree of expansion of thesegments, by the air bag, may be controlled. If desired, a lock-nut (notshown) may also be threaded onto the bolt.

It is understood that the structure illustrated in Fig. 1 is provided atten locations about the circumference at the unit shown in Fig. 3.

In order that the innermost surfaces of the rim unit may present arelatively smooth inner surface, irrespective of the degree of expansionor spreading of parts 11 or 12, the present improvements include a angemember 18 welded or otherwise firmly secured to part 11 but offset withrespect to part 12, so as to dene a recess between it and the sleeve 16.If desired however, the segments may be designed to omit the recess. Insuch a form segment 11 and flange 18 may be formed as an integral unit.Thereupon both segments 11 and 12 may be made of thinner gauge metal,thereby reducing the recess to a negligible offset. This flange 18overlaps or telescopes the part 12, as clearly seen in Fig. 1, and is ofthe same linear extent as each segment to which it is attached, so thatit also presents a complete annulus or ring along with the ve segmentspreviously referred to.

This flange element serves to cover or seal the gap or space between theparts 11 and 12, when they are spread transversely, and protects the airbag (not shown) from injury or impairment during ination or deation ofthe bag.

Complementary studs 19, integral with the segments, are provided foralignment purposes. A suitable aperture, not shown, is provided throughsome portion of the rim unit to accommodate the valve stem of the airbag.

The use of the improved collapsible curing rim unit of the presentimprovements will be obvious to those skilled in the art. Charts areprovided which tabulate the various tire sizes, the plys, etc., and suchcharts indicate the exact inner wall diameter of the tire to berecapped. For any given tire size therefore, the nuts 15 on all ten ofthe adjustable bolts 14, are initially set to limit the expansion of theSegments to a predetermined degree. Accordingly, when that degree ofexpansion is reached, the beads B and C will lightly engage the innerwall of the tire to insure an intimate contact, but no pressure of themetallic beads or edges of the curing rim will be pressed into the tireto impair or mar its interior.

After the tire to be retreaded is placed in the mold, the air bag isthereupon inserted in the tire and then the rim unit of the presentimprovements is collapsed and inserted in the tire and thenexpanded tofull circumferential or annular position. When this condition isachieved, the air bag is then inflated, and air pressure is supplied toa degree in which the air bag expands firmly against the tire, as wellas against the inner annular surface of the curing rim. Increased airpressure will force the air bag against the parts 11 and 12, and willtend to expand and separate them until a close and complete contact isarrived at between beads B and C, and the inner walls of the tire. Thiscontact serves to support the side walls of the tire within the mold.All coil springs on all the segments are therefore under compression.When this position is reached, the retreading process may continue.

During this operation, it is apparent that the beads B and C, which haveconvex faces, effect a streamlined engagement with the concave innertire walls, thereby supporting them and insuring against any impairmentof the tire. This convex surface of the beads, also insures against anypinching of the air bag or the production of any unnecessary welts inthe air bag due to insufficient or improper contact between the curingrim and the tire wall. The self-adjusting and expandable features ofthis curing rim also contribute to the same advantages above outlinedwith respect to protecting the life of the air bag. If desired the beadsB and C may be omitted.

It is apparent, therefore, that after the nuts 15 and washers 20 areset, this curing rim unit under the expanding influence of the inflatedair bag, will accommodate itself to any predetermined size of tire intowhich it is inserted. This expansion of the rim serves to force thebeads B and C against the inner walls of the tire, and in turn, hold thetire against the inner walls of the mold or matrix, so as to insureproper positioning during the retreading operations.

Obviously, upon deflation of the air bag, the pressure on the Segmentsis reduced and the coil springs restore segments 11 and 12 to the normalposition of engagement, as seen in Fig. 1. In this position, the curingrim may be collapsed and removed from the tire. It may thereafter beused in retreading operations for another sized tire by simplyre-setting nuts 15 and washers 20.

It is therefore apparent that regardless of the tize of the tire to beretreaded, the expandable curing rim of the present improvementsdetermines the extent to which the rim will be separated by the pressureof the air bag. Accordingly, this single rim structure, supplies theneed of a plurality of sizes of curing rims for a plurality of sizes oftires.

What I claim as my invention is:

1. In an apparatus for retreading automobile tires, a tire curing rimunit comprising complementary annular collapsible rim structures, eachstructure comprising a plurality of pivoted segments mounted for pivotalmovement on pivot pins, resilient means for maintaining said structuresin complementary relationship, and a segmental annular ange structurepermanently fixed to one of said annular structures, and partiallytelescoping the other annular structure.

2. In an apparatus for retreading automobile tires, a tire curing rimunit comprising complementary annular collapsible rim structures, atleast one anchor bolt and `coil spring unit for yieldingly holding saidstructures in contacting complementary relationship for affordinginsertion within a tire, each structure comprising a plurality ofpivoted segments mounted for pivotal movement on pivot pins, and asegmental annular ange structure integral with one of said annularstructures and partially telescoping the other annular structure.

3. In an apparatus for retreading automobile tires, a tire curing rimunit comprising complementary annular collapsible rim structures, saidstructures having identical diameters when extending whereby theyregister to define a common and uniform circumference, resilient meansfor yieldingly holding said structures in register and in complementaryrelationship for affording insertion within a tire, each structurecomprising a plurality of pivoted segments mounted for pivotal movementon pivot pins, and a segmental annular ange structure integral with oneof said annular structures, said flange structure extending laterallyfrom said rim structure and offset with respect thereto for partiallylapping the companion rim structure.

4. In an apparatus for retreading automobile tires, a

tire curing rim unit comprising complementary annularunit forrestricting the lateral movement of said rim structures varyingdistances for fitting within tires of various sizes.

5. In a tire curing rim structure, a pair of elongated curved segmentshaving contiguous longitudinal edges in substantial register, one ofsaid segments having a ange portion partially overlapping the othersegment, yieldable means for maintaining said segments in contiguousrelationship and adjustable limiting means for predetermining theseparation of said segments.

6. In an apparatus for retreading automobile tires, a tire curing rimunit comprising complementary annular collapsible rim structures, saidstructures having substantially identical diameters whereby theyregister to dene a common and uniform circumference, a sleeve memberhaving a recessed end portion anchored on one rim structure, a boltmember anchored on the said other rim structure and projecting throughsaid sleeve, an adjustable member mounted on said bolt, a coil springsurrounding said bolt and engaging said adjustable member and saidsleeve Within the recessed end portion thereof tending to retain saidstructures together and having its compression Varied according to theposition of said member on said bolt, each structure comprising aplurality of pivoted segments mounted for pivotal movement on pivotpins, and la segmental annular flange structure integral with one ofsaid annular structures, said flange structure eX- tending laterallyfrom said rim structure for partially lapping the companion rimstructure.

References Cited in the file of this patent UNITED STATES PATENTS

